title: Good neighbors? The effect of a level 1 trauma center on the performance of nearby level 2 trauma centers.
abstract: OBJECTIVE
  In this study, we sought to determine whether the proximity of a level 1 trauma center (TC) might affect the performance of a nearby level 2 TC.
  
  
  BACKGROUND
  With the exception of research and teaching programs, level 2 TC must function at a level similar to that of level 1 TC, and provide high quality, definitive care to severely injured patients. However, the role of a level 2 TC within a region might vary significantly depending on the local trauma care environment. We postulated that the case mix, regional role and outcomes of level 2 TC are greatly influenced by the regional presence of a level 1 TC.
  
  
  METHODS
  Data were derived from the National Trauma Databank (9.0), limiting to adults with Injury Severity Score ≥9. Level 2 TC were classified as either isolated trauma centers (ITC, >30 miles from the closest level 1 TC) or neighbored trauma centers (NTC, ≤30 miles from the closest level 1 TC). Regression was used to calculate risk-adjusted mortality at each center type.
  
  
  RESULTS
  Fifty-five thousand six hundred and fifty-five patients were identified at 161 centers; 55% of patients were cared for at ITC (n = 84 centers). Case mix varied significantly across center type; in particular, ITC received significantly more transfer patients than NTC. After adjusting for differences in case mix, patients at ITC had a 12% lower risk of death than patients treated at NTC (0.88, 95% CI 0.78-0.98).
  
  
  CONCLUSIONS
  Level 2 TC assume different roles depending on the local trauma system configuration. Ideally, a level 2 TC should benefit from the presence of a nearby level 1 TC through collaborations in care protocols and shared case reviews. However, these data suggest the opposite: level 2 centers in proximity to level 1 centers might perform at a lower than expected level.
authors.affiliation: Department of Surgery, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada. barbara.haas@utoronto.ca
authors.forename: Barbara
authors.initials: B
authors.lastname: Haas
authors.forename: David
authors.initials: D
authors.lastname: Gomez
authors.forename: Melanie
authors.initials: M
authors.lastname: Neal
authors.forename: Christopher
authors.initials: C
authors.lastname: Hoeft
authors.forename: Najma
authors.initials: N
authors.lastname: Ahmed
authors.forename: Avery B
authors.initials: AB
authors.lastname: Nathens
mesh_terms: D002170:Canada; D002423:Cause of Death; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D016208:Databases, Factual; D005260:Female; D019538:Health Care Surveys; D006297:Health Services Accessibility; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D008297:Male; D009104:Multiple Trauma / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D017063:Outcome Assessment, Health Care; D018570:Risk Assessment; D016019:Survival Analysis; D013647:Task Performance and Analysis; D014193:Trauma Centers / Q000145:classification*; D015599:Trauma Severity Indices; D014947:Wounds and Injuries / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*